1. Field of the Invention
This invention generally relates to a friction clutch having a thrust plate mounted in a housing so that the thrust plate cannot rotate but can move axially. The thrust plate is pressed toward a counterthrust plate by the force of a cup spring, a clutch disc having friction linings being interposed between the thrust plate and the counterthrust plate. The housing is fastened to the counterthrust plate, whereby the cup spring presses with its uninterrupted outside diameter against the thrust plate, and the cup spring is in contact with its inside diameter interrupted by notches, with the housing. The friction clutch also generally includes a clutch release mechanism to release the thrust plate against the force of the cup spring.
2. Background Information
Such a friction clutch is disclosed, for example, in U.S. Pat. No. 3,340,974. The friction clutch disclosed in the aforementioned United States patent generally includes a cup spring or diaphragm spring, which cup spring is supported by means of its continuous outside diameter on the thrust plate, and is located with its inside diameter, in which there are recesses to represent short flexible tongues, on the clutch housing. The thrust plate is actuated by means of radially-running levers which are mounted on the housing so that they can pivot, and which are also mechanically connected to tie bolts which are also mounted so that they can pivot. The ends of the levers pointing radially inward can be controlled by a clutch release system.
An advantage of such a cup spring clutch is the fact that the spring characteristic has a very extended curve, so that even when there is a large wear distance of the clutch, there is only a slight change in the application force. One disadvantage of such a cup spring clutch, however, is the relatively large technical effort and expense required to actuate the thrust plate. The various levers provided here with their pivot bearing are not only expensive to manufacture and install, but are also affected by friction, and typically require a relatively large amount of axial space to install.